Yellowstone probably gets more than its fair share of stupidity. The fact that there are signs everywhere telling you to not try to ride the bison or put your children on top of them for photos means someone has tried it. A 2,000 lb. animal with sharp horns and hooves, what could possibly go wrong? SMH.
I'm certain people have died there leaving the boardwalk trails and walking in areas that are clearly indicated to stay out of, they punch thru the thin crust of earth and are boiled alive in a thermal feature.